| 1. |
- Kängsepp, Pille, et al.
(författare)
-
Hydraulic performance of a full-scale peat and ash biofilter in treatment of industrial landfill leachate
- 2009
-
Ingår i: Waste Management & Research. - 0734-242X .- 1096-3669. ; 27:5, s. 512-519
-
Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to evaluate the hydraulic performance of a full-scale on-site vertical-flow biofilter, consisting of a mixture of peat and carbon-containing ash, and a 500 m3 equalization pond prior to the filter-system. The treatment plant was constructed to clean up leachate from an industrial mono-landfill that contained shredder residues of end-of-life vehicles and white goods. With the limited storage capacity of the equalization pond, peak loading rates exceeded up to five to six times the designed daily hydraulic load limit of the biofilter system. Such relatively short overloading events did not negatively affect the purification efficiency. To provide the designed annual irrigation rate on the biofilter of 97 m3 day— 1 (or 133 mm day—1), with large seasonal variations in precipitation, a relatively large pond would be needed. Calculations showed that a storage volume of about 23 000 m3 would be sufficient for annual leachate volumes up to about 35 000 m3. A combination of sprinkler and drip irrigation with straw insulation of the latter made it possible to run the plant continuously even when the ambient air temperature was below zero for more than a month at a time. The grain size distribution of the biofilter medium was noticeably changed after 4 years of usage due to the loading of suspended solids from the leachate and decomposition of the peat, causing reduced hydraulic conductivity.
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
- Minh Tran, Thao, et al.
(författare)
-
Capacity of Vitiver grass in treatment of a mixture of labaratory and domestic wastewaters
- 2015
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this study, laboratory wastewater containing organic matters, heavy metals and aromatic compounds, was treated by vetiver grass (Vetiveria zizanioides) as a phytoremediation method to remove the above three groups of pollutants. Sewage effluent, as a source of nutrient supply for plant growth, was firstly fed to two wetland systems: mini horizontal subsurface flow (HSSF) and floating raft (FR) wetlands. Next, laboratory wastewater was added gradually to mix with sewage. Nominal hydraulic retention time in both wetlands are 12 hours. Pollutants removal efficiencies were monitored. Microbial community change corresponding with each stages of sewage only and mixture with laboratory wastewater was also examined. The examined microbial community includes Nitrogen-fixing (N-fixing) bacteria, Phosphate-solubilizing (P-solubilizing) microorganism, Pseudomonas sp., and Zoogloea sp. In HSSF wetland, base materials (gravel and sand), algae, and vetiver root were in turn investigated for pollutant removal efficiencies. The results reveal that even with the presences of heavy metals and aromatic compounds, vetiver presented reasonable removal efficiencies of about 62%, 68.6%, and 58.3% for BOD, TN, and TP removal, respectively. Base materials showed almost no effect on pollutant removal. Algae was slightly responsible for approximate 6.3%, 16.6%, and 19.7% of BOD, TN, and TP removals, respectively. On the other hand vetiver roots, in term of heavy metals, had an impressive removal efficiencies of 99.2, 95.8, 96.2, and 96.7% of Cr+6 (in K2Cr2O7), Mn (MnSO4), Fe (FeSO4), and Cu (CuSO4), respectively. For aromatic compounds, the wetland is responsible for 96.8 and almost 100% of correspondingly phenol and benzene removal efficiencies. For microbial aspect, N-fixing microorganisms (e.g. Azospirillum sp., Azotobacter sp.) and Phosphate-solubilizing bacteria (Bacillus sp.) increased gradually in population during domestic wastewater feeding stage. When laboratory wastewater was added, N-fixing and P-solubilizing bacteria werequantitatively decreased slightly while population of Pseudomonas sp. increased. Besides, Zoogloea sp. was also found increasing through out the experiment and keeping a stable growth even during laboratory wastewater adding. In FR wetland, both algae and vetiver root were also investigated for BOD and aromatic compounds and heavy metals. The outcomes show similar tendencies in treatment and microbial behaviours as in HSSF wetland. Vetiver grass, mainly responsible for organic matters and nutrients removal, presented slightly lower removal efficiencies than those in HSSF wetland. The average values of removal efficiencies are 59%, 63.5%, and 53.0% for BOD, TN, and TP removal, respectively. Algae, also, took minor responsibility for approximate 3.3%, 9.1%, and 8.9% of BOD, TN, and TP removals, respectively. Heavy metals of Cr+6 (in K2Cr2O7), Mn (MnSO4), Fe (FeSO4), and Cu (CuSO4) were found removing less than in HSSF wetland with average removal efficiencies values of 92.4, 85.1, 91.8, and 91.5%, respectively, by vetiver root. Algae show almost no effect on heavy metals and aromatic removals. The vetiver root likewise plays important role in phenol and benzene removals with values of 91.5 and 96% in efficiency, respectively. N-fixing and P-solubilizing microorganisms, Pseudomonas sp., and Zoogloea sp. presented similar responses tendencies to different living condition when domestic and laboratory wastewaters, in turn, were fed.
|
|
| 8. |
- Angelstam, Per, et al.
(författare)
-
Solving Problems in Social-Ecological Systems : Definition, Practice and Barriers of Transdisciplinary Research
- 2013
-
Ingår i: Ambio. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 42:2, s. 254-265
-
Tidskriftsartikel (refereegranskat)abstract
- Translating policies about sustainable development as a social process and sustainability outcomes into the real world of social-ecological systems involves several challenges. Hence, research policies advocate improved innovative problem-solving capacity. One approach is transdisciplinary research that integrates research disciplines, as well as researchers and practitioners. Drawing upon 14 experiences of problem-solving, we used group modeling to map perceived barriers and bridges for researchers' and practitioners' joint knowledge production and learning towards transdisciplinary research. The analysis indicated that the transdisciplinary research process is influenced by (1) the amount of traditional disciplinary formal and informal control, (2) adaptation of project applications to fill the transdisciplinary research agenda, (3) stakeholder participation, and (4) functional team building/development based on self-reflection and experienced leadership. Focusing on implementation of green infrastructure policy as a common denominator for the delivery of ecosystem services and human well-being, we discuss how to diagnose social-ecological systems, and use knowledge production and collaborative learning as treatments.
|
|
| 9. |
- Punzi, Marisa, et al.
(författare)
-
Combined anaerobic-ozonation process for treatment of textile wastewater : Removal of acute toxicity and mutagenicity
- 2015
-
Ingår i: Journal of Hazardous Materials. - : Elsevier BV. - 0304-3894 .- 1873-3336. ; 292, s. 52-60
-
Tidskriftsartikel (refereegranskat)abstract
- A novel set up composed of an anaerobic biofilm reactor followed by ozonation was used for treatment of artificial and real textile effluents containing azo dyes. The biological treatment efficiently removed chemical oxygen demand and color. Ozonation further reduced the organic content of the effluents and was very important for the degradation of aromatic compounds, as shown by the reduction of UV absorbance. The acute toxicity toward Vibrio fischeri and the shrimp Artemia salina increased after the biological treatment. No toxicity was detected after ozonation with the exception of the synthetic effluent containing the highest concentration, 1. g/l, of the azo dye Remazol Red. Both untreated and biologically treated textile effluents were found to have mutagenic effects. The mutagenicity increased even further after 1. min of ozonation. No mutagenicity was however detected in the effluents subjected to longer exposure to ozone. The results of this study suggest that the use of ozonation as short post-treatment after a biological process can be beneficial for the degradation of recalcitrant compounds and the removal of toxicity of textile wastewater. However, monitoring of toxicity and especially mutagenicity is crucial and should always be used to assess the success of a treatment strategy. © 2015 Elsevier B.V.
|
|
| 10. |
- Punzi, Marisa, et al.
(författare)
-
Degradation of a textile azo dye using biological treatment followed by photo-Fenton oxidation : Evaluation of toxicity and microbial community structure
- 2015
-
Ingår i: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 270, s. 290-299
-
Tidskriftsartikel (refereegranskat)abstract
- Many commercial dye preparations are cocktails of active dyes and various by-products that are recalcitrant to biological degradation and end up in significant amounts in the effluent after the dyeing process. Conventional wastewater treatment processes are not able to degrade such compounds and detoxify the effluent, thus alternative treatments should be developed.In our work we suggest to use photo-Fenton oxidation as post-treatment after an anaerobic biofilm process, in a way to minimize the reagents needed. This process was used for treatment of synthetic textile wastewater containing the commercial azo dyestuff Remazol Red, starch and sodium chloride. The treated textile effluent had COD lower than 18. mg/l even when using initial Fenton reagents concentration as low as 1. mM ferrous ions and 10. mM hydrogen peroxide. The acute toxicity was higher in the biologically treated than in the untreated effluent. Photo-Fenton oxidation successfully reduced the toxicity and the final effluent was non-toxic to Artemia salina and Microtox, with the exception of the effluent containing high concentration of sodium chloride, which was moderately toxic to Microtox. For the first time the presence of algae was detected in a reactor treating textile wastewater using denaturing gradient gel electrophoresis (DGGE); bacteria and fungi were also abundant.The results of this study suggest that using advanced oxidation after biological treatment is an effective way to degrade the organic compounds and remove toxicity from textile effluents.
|
|
